Gearing - double vs. triple

My name is Doug and I have been a lurker here for the past weeks. I should point out that I am seeing help for it though.

I was hoping I could solicit some feedback from everyone. My wife and I have just ordered a new tandem, a Co-Motion Macchiato, built up with Campy Record. This will be our second Co-Motion, fourth road tandem and fifth tandem all around. While we have certainly gained plenty of insight with all of the different tandems that have passed through, it has also created somewhat of a monster here as I look to tweak every bit of the new bike. The most recent change has been to drop the FSA cranks from the build and go with a set of DaVinci cranks instead. (My wife and I top out at maybe 235 lbs as a team, so there is absolutely no concern about going with a standard BB as opposed to one with outboard bearings.)

With that explained, here is the question. Every tandem out there comes with triple cranks. Is anyone running their tandem with a double set up and if so, what has your experience been? We are considering going that route as we believe it will fit our riding style better. I log anywhere from 100-150 miles a week on my single with a low of 39/25 and rarely find myself for want of a lower gear. My wife spends no other time on a bike, but is a runner, so we have similar fitness. In addition, we have similar preference for a higher cadence. While I know climbing on a tandem is nothing like a single (and yes, we certainly use the 22/30 on our MTB tandem), most of the riding we will be doing will be rolling terrain that can easily be handled by a 39/25 if not a 34/25. Thanks in advance for the feedback.

If you were constrained by your components it would be an issue, but if you're going with the daVinci cranks you have all kinds of options... to include same-side drive... and most of them don't lock you in or out of making a configuration change later-on. A long-cage rear derailleur while not ideal for dual drive, also gives you future flexibility if you want to cover your bases.

In other words, because the daVinci cranks use a square spline and bolt-on main drive spider and spider-less cranks you can:

1. Run a standard 110/74 BCD spider for a compact crank configuration
2. Have a second set of chainrings with a granny to reconfigure as a standard triple

You could also decide later on that what you really needed was a 130/74 BCD crankset and obtain a second bolt-on spider with the 130/74 BCD spacing and the right size of chainrings to reconfigure your daVinci cranks. 4-bolts and a slight press-fit on the crank arm's square spline are all that hold the spiders and timing rings on the daVinci crank arms.

Finally, as mentioned, you could also specify that both captain's cranks have the square spline and you could run a 34t timing ring on your right front crank and mount a 34t chainring in the granny ring position on a triple crankset to have a right-side / same side drive configuration with the big and middle ring set up as your dual drive.

Again, lots of options that allow you to change your mind later-on.

While we've always used triple cranksets, the granny ring is rarely used. However, when it's needed it's always nice to have and the weight penalty (75 - 100 grams?) isn't all that bad. We've ridden with a number of teams who have either had doubles or who had on 12x23t or 12x25t cassettes who didn't realize how steep some of the mountains would be in places like North Georgia or Tennessee. Most of them grunted up the hills, where others had to bail. Again, having the daVinci triple mounted to the bike on a 130mm spider doesn't preclude keeping that Alpine chain wheel and bolts/spacers in your tool kit "just in case". The latter is obviously true of other triple cranksets.

...but if you're going with the daVinci cranks you have all kinds of options... to include same-side drive... and most of them don't lock you in or out of making a configuration change later-on.

Having never spent time exploring the daVinci cranks in person (on-line only), combined with the fact that there is no longer a shop around here with anything more than a passing focus on tandems, I wasn't aware of the complete flexibility these cranks had in terms of set up. This certainly reinforces the decision to go with them. Have you ever tried the same side drive set up? Positives? Negatives? Thanks.

Welcome to the forum!
Our first tandem in 1975 indeed was a true '10-speed' . . . 2 chainrings, 5 cogs, French Follis.
Perfectly do-able, but then we were only in our early 40s.
However as we age a bit, or get to do some serious long/steep climbs, the value of 3rd chainring becomes apparent. Save them knees . . . got over quarter million miles on 'em and they're still working flawlessly.With the daV crankset it leaves you open to changes/options.
Our take on double vs triple: Better to have it and not need it, than to need and not have it.
Pedal on TWOgether!
Rudy and Kay/zonatandem

1. When building a tandem it allows you to use a pair of standard triple cranks vs. buying a tandem cross-over crankset. This pretty much means you can use any single bike triple cranks that suit your fancy. For example, off-road tandem folks who opt for the Rolhoff hub can use a pair of Shimano XT cranks.

2. It reduces wear and tear on the stoker's bottom bracket by eliminating the torsion loads that run through the spindle which is being pulled forward on the left side of the tandem by the captain's pedal loads, while the right end of the spindle is pulled backwards by the drive train loads.

3. It puts all of the drive train components on the right side of the tandem, leaving the left side "clean".

4. It eliminates one timing ring and a crank spider on conventional timing cranks.

5. It draws lots of attention because maybe one out of 1,000 tandems are set up this way, although this could be a negative to some teams.

Cons:

1. Running a triple with single/same side drive can get tricky and is usually best left to the cross-over crankset.

2. It puts all of the frame bending loads on one side of the frame... probably not a big deal but, heh, it is what it is and some builders make a big deal about boom tube deflection. This configuration just moves it over to the same side of the bike that's already loaded up between the rear axle and bottom bracket on the right side.

We are using a double chain ring on our Seven. We have a 55x44 with a 11x25 cassette with Campy Record components including a short cage rear. It is really smooth shifting and I like the close range spacing

We would probably make some changes if we were to ride mountains. So far it has worked well for us riding in Minnesota and Tuscany. It all depends upon the terrain you are riding in and the effort you want to expend for climbing.

We have a triple. We never use the small ring on any of our local rides on the East (flat) side of Orlando, FL. We've used it on almost all the rides we've traveled to.

If you're ever going to have aspirations of riding outside of your flat terrain, go ahead and get set up with the triple. $ & G penalties are relatively low. If you don't get out of town much, and don't plan to, the double may be adequate.

I am so used to a double set up on the road. Purely from a muscle memory perspective, I can drop from the large to small ring while shifting from a larger to smaller cog (or vice-versa) and nail the gearing so the cadence is spot on 95% of the time. It would be nice to keep with that. Agreed about changes to the set-up if we are riding in the mountains, but in that case we might just pull out the MTB tandem and go off road.

Thanks for the perspective on the pros / cons for same side drive. The one that kept sticking in my head would be what would happen if the chain dropped off the middle ring. Could certainly be interesting. Regarding the bottom bracket, I am going to think positive that Phil Wood will deliver something that will hold up with no issues for a light team that prefers to spin.

I am noticing a pattern here that everyone running a double set up is topping in the 55 range. Are you finding that you are coming close to spinning that out? We were actually thinking about going compact to give us more range for climbs. I can't remember the last time I spun the gearing out with a 53/11 and while there is certainly more speed on the downhill with the tandem, we generally find more speed by tucking and letting the bike run.

We have a triple. ... We've used it on almost all the rides we've traveled to.

With the previous Co-Motion, I can think of two times we really took advantage of the triple. Once in Colorado traversing the Continental Divide (not in peak fitness at the time) and on a ride in Northern California where we hit a 22% grade. Other than that, for 99% of our riding we found the middle ring was a little too tall and the inner ring was too low.

Of course now having said that, we'll probably find ourselves wanting a triple more often than not.

I am going to think positive that Phil Wood will deliver something that will hold up with no issues for a light team that prefers to spin.

Having torn-up a somewhat exotic Ti bottom bracket's aluminum end-cap back in '99 due to spindle deflection and being a lightweight team that spins in the mid-80's to mid-90's on the tandem, I've been using steel spindles ever since. In looking at the three Phil BB axle options -- Stainless, Ti, and Super-Duper Ti -- I opted to split the difference and use the stainless for the stoker's BB and the basic Ti model for my BB.

SRAM makes an 11-26. I don't need the 11 since we are spinners and don't try to set speed records just yet on every downhill so I have a 12-27. Don't know if that is what you meant by tighter?

Thank you....I very much want the 11... and I am not sure I can handle all the hills in the area all the time in a 26. I almost never need to go lower than our 25.. but I am not sure If I want my lowest to be a 42-26...

Given that the double and the triple shift with equal reliability and that the high and low of the system are the same, measured in ratio or gear inches, the advantage of the triple over the double is narrower splits between the gears, because the same range is spread over more steps. If it matters to you, you can stay closer to the optimum cadence more often with a triple. If you want to ride with a pack of singles, it makes sense to gear like the singles, so I prefer to use 53-39-28 chainrings, and the smallest cassette I can get away with (11-21 is ideal) for the terrain of the day.

Depends on where you are riding and your stoker. Personally, I'd stay with the triple. It doesn't cost that much in weight and you need an out gear now and then. We are running a triple with an 11/34 here in the flatlands. Granted, we rarely use the small cog, but we when we need it we really need it (On the Hilly Hundred, for instance). We don't have a lot of long hills here, but there are some short steep climbs that, for us, demand a low gear. We find the gearing on our Co Motion to be a little odd too. We have a 53/39, but I would rather have a 55/42, I think. We mostly run the big ring around here, as we spin the middle ring out most of the time. Good idea about trashing the outboard crank, I went through a set of bearings on my single in less than 10000 miles.

I'm with Dude. We're in the process of building a new bike,..and I'm wrestling with the same issue. I would like to do the Compact thingy,...mostly for the narrower Q for my stoker. And like you guys, we typically coast and tuck on the longish descents and a 50/14 allows for 25 mph at a reasonable cadence. Of course the whole gearing thing is so personal. I'm sure we all know what we need,..gearing wise,...recognizing some like pushing a big gear up long steep hills,...while others prefer the sit 'n sping thing. More important is the terrain we are not familar with,...and that's where the extra gearing may come in handy. I've gone to France a few times,..and in preparing,..I have thoroughly evaluated the various climbs we were planning on riding,...and they were always harder than I anticipated. Ya'd think 9% is 9% wouldn't you?

I want to thank everyone for their input on this question. It has been a HUGE help. The final decision, and thank you to SDS for pointing out the obvious, was to go with a triple that would be set up the same as my single (53/39) with the addition of an inner ring. Not sure why I couldn't think of that on my own considering the obsessing I am doing over every details, but alas... Still debating what to go with for the inner ring, but we'll sort that eventually.

I'm with Dude. We're in the process of building a new bike,..and I'm wrestling with the same issue. I would like to do the Compact thingy,...mostly for the narrower Q for my stoker. And like you guys, we typically coast and tuck on the longish descents and a 50/14 allows for 25 mph at a reasonable cadence. Of course the whole gearing thing is so personal. I'm sure we all know what we need,..gearing wise,...recognizing some like pushing a big gear up long steep hills,...while others prefer the sit 'n sping thing. More important is the terrain we are not familar with,...and that's where the extra gearing may come in handy. I've gone to France a few times,..and in preparing,..I have thoroughly evaluated the various climbs we were planning on riding,...and they were always harder than I anticipated. Ya'd think 9% is 9% wouldn't you?

GOOD luck and keep us informed.

Rich

I ride a compact (50/34) single and I would have some qualms about using that on the tandem. It works for the low end fairly well, but I spin out my 50/12 on some rides around here and I would, for sure, spin that out using the tandem. The 50/11 is another story, but I don't always have that mounted.

we typically coast and tuck on the longish descents and a 50/14 allows for 25 mph at a reasonable cadence. Of course the whole gearing thing is so personal. I'm sure we all know what we need,..gearing wise,...recognizing some like pushing a big gear up long steep hills,...while others prefer the sit 'n sping thing. More important is the terrain we are not familar with,...and that's where the extra gearing may come in handy.
Rich

On the few clean descents we've done, we've spun the 53/12 downhill to 34-35'ish MPH or until I start to get yelled at to stop pedalling, then coasted up to 40, and tucked to get about 44.

I'll have to ask permission to get more than that on our next trip downhill on the steeps.

A triple allows a close ratio cassette! One can always be in the right gear, or in the sweet spot, and that always makes me much happier. With what I call a "tandem compact crankset" (~53/39/28) with an 11-21 or 11-23, you will always have the right gear, be able to do most climbs, and have a good downhill top end. (53/11 is a higher gear than 55/12)

Our good friends run a double. It occasionally limits where they/we can ride.

Hello all; I've been lurking around the WWW doing some research for, if all goes as planned, my first tandem purchase in time for the spring. I find this discussion very interesting, as double vs triple cranks is one of the main topics that keeps popping into my head. I'm full of ideas but don't have a grasp on reality, never owning a tandem. By the way, I have my sights set on the Co-Mo Periscope Trident Convertible, 700c, for family transport/recreation as well as racing. We have two kids, aged 3 and 5, and I had thought about a quad, but it is usually only one of us parents at a time that is looking after them and wants to go somewhere or for a ride. If we all travel together, one of us can ride a single. Note to self: will have to ask Co-Motion about the logistics of a Periscope Quad Convertible (to triple or double) ...

Anyways, for one, I have been a bit astounded at the prevalence of triples and high range gearing in general for tandems. Is this because tandems do not climb as well as singles, or is it that tandems are more well-travelled, i.e. get ridden in more locations and more varied terrain, and possibly need to be more versatile than say a road racer?

On my two road machines, one of which weighs ~40lb with its homemade 55W light set, I use a single 52T ring mounted on 165mm track cranks, with 12-21 and 12-23 rear clusters. The chain rarely engages anything bigger than 17T. I find that using the bigger gears up hills makes me go faster, but the hills around here aren't more than a minute or two long. I wonder if lower gears are often used as a crutch when not really necessary. On my racing bike the 52-21 combo is rarely used and I can get up almost anything without going past the 19. For a really hilly road race in '92, Tour de White Rock, I put a 48 on the front.

Based on this, it would seem likely that a double chainset would be sufficient for tandem use, but I'm still not sure. With a 55/42 up front and a 12-27 10-sp cluster, I would have access to far lower gears than with my singles and still have a straight run from 12-17 for hammering, but, and a big but it is, I have to take into account that the wife (strong) will be using it regularly to transport the kids and there could be multiple stokers/captain possibilities. I would love to get into the tandem racing scene, especially TT events.

One aspect of the double vs triple chainring consideration that has not been mentioned is q-factor, which, I would think, will be wider with the triple. This is what I have observed, but most of the triples I see are on cheap MTBs. Are there narrow-q triples out there? I suppose the cranks could be swapped between double and triple as required. For example, especially if entering the tandem in a TT, I might want double cranks on there if I will be stoker, being accustomed to the narrow q factor of track cranks. Are the road triples, Ultegra for example, any wider than the doubles? I've tried to find info on q-factor for various cranks but it is lacking. It's sounding more and more like having a triple back there is a good idea for us, but I still wonder. Would the granny gears be used as a crutch?

I like the idea of a single-side drive configuration. Wouldn't the stress on the boom tube be lower than crossover drive? Cranks rear of the captain's would have their chain tensions cancelled out between the chain that runs forward and the one that runs rearward. The downside of running a sync chain to the small ring of a triple, is that the small rings will generate more chain tension and will wear themselves and the chain faster. In fact, I'm surprised that sync chainrings aren't bigger than they are. Why aren't they, say, 52T? They would cause less stress on drivetrain components and the frame. Has anybody tried/considered this: http://www.bikexprt.com/bicycle/tancrank.htm